1. Field of the Invention
The present invention relates to a rechargeable battery pack. More particularly, the present invention relates to a rechargeable battery pack including a cap cover on which a protection element can be easily mounted and a coupling terminal which is integrally manufactured when forming the cap cover.
2. Description of the Related Art
As the fields and demand for rechargeable batteries increase significantly, various methods for fabricating rechargeable batteries are being suggested. Among them, a battery pack is a good example. That is, a plurality of unit cells of the rechargeable battery are bound into a bundle and then used as one battery.
The battery pack is a battery in which a plurality of unit cells are bound as a bundle. A plurality of bare cells, or a plurality of core packs are electrically connected either serially or in parallel with each other and are then sealed within a pack case. Such a battery pack is used for increasing charging capability or a supply voltage, and is mainly used in devices, such as notebook computers, and in hybrid vehicles which need to be operated for a long time and be driven by a high capacity power source.
The bare cell of the battery pack has an identical structure to that of a unit cell. It includes a can, an electrode assembly accommodated inside the can, and a case for sealing the electrode assembly. As noted above, the rechargeable battery which is composed of a can, an electrode assembly and a case is called a bare cell, and the rechargeable battery is called a core pack when a protection circuit is attached to the bare cell.
In a prismatic rechargeable battery, there is a problem in that arranging a safety device is more difficult than arranging a safety device in cylinder type rechargeable battery due to restrictions of shape. That is, the cylinder type rechargeable battery has a safety device which blocks a flow of current by being ruptured when an internal pressure of a battery increases, but in the prismatic rechargeable battery, only a safety device including a safety vent and a temperature-responsive element is arranged. Furthermore, in a battery pack using the prismatic rechargeable battery, since a process for attaching a temperature-responsive element on the outside of the bare cell is very complicated, there are problems in that the manufacturing cost increases, and the yield reduces. However, if a temperature-responsive element is omitted in order to reduce the manufacturing cost and to increase the yield, then the safety of such a rechargeable battery is deteriorated tremendously. Therefore, a method and a structure for easily mounting a temperature-responsive element are urgently required.